Typical speeds for bicycles are 10-15 mph or 15-25 km/h.
On a fast racing bicycle, a reasonably fit rider can ride at 30 mph or 50 km/h on the flat for short periods.
The highest speed ever attained on the flat, without riding behind a wind-block, is by Canadian Sam Whittingham, who in 2001 set a 80.55 mph or 142.51 km/h record on his highly aerodynamic recumbent bicycle.
This stands as the record for all human-powered vehicles.

The first successful machines that resembled bicycles were invented in the early 1800s.
The "draisine" of 1817 had two inline wheels connected to a wooden frame by forks, and the front wheel was steerable. It became rather popular, especially in England and America.

The draisine and machines like it went by a variety of names, such as hobby horse, dandy horse, biciped or swift walker.
They were more like scooters than bicycles, because the only means of propulsion was to push against the ground.

In 1840 the Scottish blacksmith Kirkpatrick McMillan[?] designed and built the first rear-drive bicycle with pedals and cranks, and can therefore be credited as the inventor of the modern bicycle.
MacMillan called his machine a "velocipede", and rode it the 40 miles from his home to Glasgow.
On his approach to the city, crowds gathered on the road and unfortunately Kirkpatrick collided with a young girl.
Although she was only very slightly injured, he was subsequently charged with causing the first ever bicycle accident.
The judge could not believe Kirkpatrick had travelled the 40 miles to Glasgow in only 5 hours, but after much explaining, he was allowed to return home.
Kirkpatrick McMillan never patented his designs, and his key role in the development of the modern bicycle has been largely unrecognised.

Machines similar to the "velocipede" became very popular after 1866, which is when Pierre Lallement obtained a US patent for a machine he called the "bisicle".
Others called it a "boneshaker", an appropriate name for a contraption with steel-rimmed wooden wheels.

Solid rubber tires appeared in 1869 and improved the ride somewhat.
The front wheel got bigger, and the rear wheel got smaller.
A bicycle boom began.
The first highwheeler or 'Ordinary' appeared in 1872.
This was called a "Penny Farthing" in England (a penny representing the front wheel, and a much smaller coin, the farthing, representing the rear wheel).

Since a large wheel went farther for each turn of the cranks, and since the maximum pedalling speed was limited, the larger the wheel, the faster a rider could go.
Some of the highwheelers had wheels nearly 60" in diameter.
They were fast.
They weren't particularly safe.
The rider was way up in the air and travelling at a great speed. If he hit a bad spot in the road he could easily be thrown over the front wheel and be seriously injured or even killed.
"Taking a header", which was not all that uncommon, was no joking matter.

In 1884, J. K. Starley[?] of the Coventry Sewing Machine Company, invented the "safety bicycle" with wheels of moderate size and a chain drive.
With the rider sitting far back on the bicycle, it was almost impossible to take a header on such a machine.
With the front chainwheel larger than the rear sprocket, the rear wheel turned faster than the cranks, making it possible for a chain-driven bicycle to go fast even without a huge wheel.

The safety bicycles of 1890 were very much like today's bicycles.
They had pneumatic tyres similar in size to those on a modern bicycle, spoked wheels, a steel frame and a chain drive.
About all they didn't have was a method of changing the gears.

Multi-ratio gearing systems were present in racing bicycles by the 1930s, and derailleur systems evolved in the 1950s.

Socially, the bicycle helped to strengthen the gene pool for rural workers.
It tripled their courting radius on the one day per week they had off and thus was a factor in reducing rural inbreeding.
The two-wheeled, diamond-frame safety bicycle (basically the same one we ride today) gave women unprecedented mobility, freed them from corsets, and contributed to their emancipation.

In cities, bicycles helped reduce the crowding in inner-city tenements by allowing workers to commute from single-family dwellings in suburbs.
They helped reduce people's dependence on horses.
They allowed people to travel in the country.
They were three times as efficient as walking and three to four times as fast.
Moreover, in terms of distance and speed travelled compared to energy consumed, the bicycle is the most efficient machine yet created.

On an historical note, the development of the modern bicycle had two important implications.
First, manufacture of the double-diamond-frame safety bicycle required the development of advanced metalworking techniques to produce the frames, and components such as ball bearings, washers and sprockets.
These techniques later enabled skilled metalworkers and mechanics to develop the components that were used in early automobiles and aircraft.
The best examples were the Wright Brothers, who got their start as bicycle mechanics.

The second major implication of the bicycle was the political organization of bicycle riders and enthusiasts in such groups as the League of American Wheelmen, in order to persuade local and state governments to create a system of well-maintained and mapped paved roads.
Both the model of political organization and the roads themselves later facilitated the growth in the use of another type of wheeled vehicle, the automobile.

In some Western societies, after World War II the bicycle was largely relegated to a device for children, particularly in the United States.
In some western countries, most notably the Netherlands and Germany bicycle use for transportation remained fairly common.
However, interest has gradually returned, mostly as a fitness activity, hobby, and competitive sport.
However, more and more people are using it as a short-range transportation tool, particularly in large, densely populated cities where slow vehicle traffic, high registration and parking costs, and environmental concerns have made commuting by automobile less attractive.
This trend has been accelerated by the process of "gentrification" of the inner suburbs of many cities.
Many cities are now providing cyclist-only lanes on roads, as well as cycle trails, for both commuting and hobbyist cyclists.

The bicycle remains a primary means of personal transportation in many developing countries.
The image of Asian cities clogged with bicycles is a common stereotype, though as they become wealthier it is becoming less popular.
According to the magazine, The Economist, one of the major reasons for the proliferation of Chinese-made bicycles on foreign markets is the increasing preference of its own citizens for cars and motorcycles.

Although the operation of a bicycle is simple in principle, many of the parts are complex and some people prefer to leave repair and maintenance to professionals.
However, many prefer to maintain their own bicycles as much as they can, whether to save money or because they enjoy repairs as part of the hobby of cycling.
For more information on the technical aspects of bicycles, see the following:

"Kirkpatrick McMillan and the Bicycle (http://www.antonnews.com/plainviewoldbethpageherald/1999/06/18/opinion/mcmillan)" - an opinion article from the Plainview Herald, by Robert R. McMillan, dated Friday, June 18, 1999